[fnordprefect]

> the ovoid engine inlets

The original design of the 737 did not have ovoid inlets.

You can see regular circular nacelle inlets on the 737-100:

https://secure.boeingimages.com/archive/Boeing-737-100-2JRSX...

and on the 737-200 here:

https://secure.boeingimages.com/Assets/V2/jrZYYwCXohU1rDmk4e...

The ovoid inlet design was introduced with the 737-300, when the engine was changed to the CFM56.

[AWildC182]

The ovoid engines were a result of high bypass engines being added on the 300. The low bypass turbines on the older models was much smaller. These were then removed on the max because the engine was mounted higher and further forward on a low profile pylon.